Pump for Supplying Chemical Liquids

ABSTRACT

An opening  22   d  of a supply/withdrawal passage  22   b  is positioned at the center part of the internal wall surface  22   c  of the operating chamber  26  (concave area  22   a ), and a cross-shaped venting groove  22   e  extending from the opening  22   d  of the passage  22   b  to the periphery of the wall surface  22   c  is formed in the wall surface  22   c . Thus, an operating air in the chamber  26  is discharged (sucked) through the passage  22   b  during drawing in the chemical liquid. Since the opening  22   d  communicates with the venting groove  22   e  extending to the periphery of the chamber  26 , if the center of the diaphragm  23  covers the opening  22   d  first, the operating air in the chamber  26  can be continuously evacuated (drew out) from the venting groove  22   e  positioned on the outside of the center part which first comes into contact with the opening  22   d

TECHNICAL FIELD

The present invention relates to a pump for supplying chemical liquidsthat is suitable for applying a predetermined volume of a chemicalliquid, such as a photoresist liquid, to individual semiconductor wafersin the chemical-using process of, for example, a semiconductormanufacturing device.

BACKGROUND ART

In order to pump a chemical liquid such as a photoresist out of a bottleand apply a predetermined volume of this liquid to individualsemiconductor wafers, a pump for supplying chemical liquids such as thatdisclosed in Patent Document 1, for example, is currently in use. Thispump is divided by a diaphragm into a pump chamber and an operatingchamber (a pressurization chamber in Patent Document 1), and driving thediaphragm by supplying air to or withdrawing air from the operatingchamber, via a supply/withdrawal passage connected to the operatingchamber, changes the volume inside the pump chamber, thereby causing thepump chamber to suction or discharge a chemical liquid.

When the pump chamber and the operating chamber are formed to be thinand the pump is made thin through the use of a diaphragm comprised of aflexible film, the diaphragm is secured at its perimeter, andconsequently tends to deform more at its center. At the same time, toensure efficient deformation of the entire diaphragm, it has beenpreferable to position the opening of the supply/withdrawal passage inthe operating chamber in its center.

When the interior of the operating chamber is evacuated in order to drawthe chemical liquid into the pump chamber or when the interior of theoperating chamber is opened to the surrounding atmosphere in order tosupply the pressurized chemical liquid, the diaphragm begins to deformat its center toward the operating chamber, with the result that thecenter tends to come into contact with the internal wall of theoperating chamber first. In such a case, the center of the diaphragmblocks the opening of the supply/withdrawal passage while the areasurrounding the center of the diaphragm does not contact the internalwall of the operating chamber. This slows down the deformation of thediaphragm toward the operating chamber, and moreover, may prevent thediaphragm from deforming fully. As a result, it may take a long time forthe chemical liquid to fill the pump chamber or it may not be possibleto supply the pump chamber with the specified volume of chemical liquid.

Patent document 1: Japanese patent application publication No.2003-49778

DISCLOSURE OF THE INVENTION

A primary object of the present invention is to provide a pump forsupplying chemical liquids that can ensure quick and reliabledeformation of the diaphragm toward the operating chamber, and that canshorten the time needed for filling the pump chamber with a chemicalliquid and ensure that the pump chamber is filled with a sufficientvolume of chemical liquid.

A pump for supplying chemical liquids according to the present teachingis configured as described below. That is, in a pump for supplyingchemical liquids in which the pump chamber and operating chamber aredivided by means of a diaphragm comprised of a flexible film, thediaphragm deforms toward the pump chamber when the interior of the pumpchamber is pressurized using an operating gas, thereby discharging thechemical liquid that has been supplied into the pump chamber; and whenthe interior of the operating chamber reaches a negative pressurebecause of the withdrawal of the operating gas or when the interior ofthe operating chamber is opened to the surrounding atmosphere, thediaphragm deforms toward the operating chamber, thereby drawing achemical liquid into the pump chamber, and

a supply/withdrawal passage for supplying the operating gas to orwithdrawing same from the operating chamber is formed in the pumphousing, and the opening of the supply/withdrawal passage is provided inpart of the internal wall surface of the operating chamber, and

a venting groove that extends from the opening of the supply/withdrawalpassage to the periphery of the internal wall surface is formed on theinternal wall surface of the operating chamber.

In this pump for supplying chemical liquids, the opening of thesupply/withdrawal passage is provided in part of the internal wallsurface of the operating chamber, and a venting groove is formed, whichextends from the opening of the supply/withdrawal passage to theperiphery of the interior wall surface. Here, when the chemical liquidis to be drawn in, the operating gas inside the operating chamber isevacuated (sucked out) through the supply/withdrawal passage. In thiscase, the diaphragm tends to deform from its center, which may cover theopening of the supply/withdrawal passage first. However, the opening ofthe supply/withdrawal passage is connected to the vent groove, whichopens toward the periphery of the operating chamber as described above.Therefore, even when the diaphragm deforms from the center, thuscovering the opening of the supply/withdrawal passage first, because theventing groove positioned on the outside of the contacted center isopen, it is possible to continue to evacuate (draw out) the operatinggas inside the operating chamber through the open venting groove. Inthis way, even when such uneven deformation occurs in the diaphragm, thediaphragm still quickly and reliably deforms toward the operatingchamber, shortening the time needed for filling the pump chamber withthe chemical liquid, and filling the pump chamber with a sufficientvolume of chemical liquid.

Note that it is desirable to position the extension destination of theventing groove as close as possible to the periphery of the operatingchamber, and it is best to extend it to the periphery. With such aconfiguration, the diaphragm will not block the venting groove until thediaphragm has sufficiently deformed toward the operating chamber,ensuring reliable evacuation (drawing out) of the operating gas from theoperating chamber.

In a preferred embodiment of the pump for supplying chemical liquids,the internal wall surface of the operating chamber is circular in shapeand the opening of the supply/withdrawal passage is positioned in thecenter of the internal wall surface of the operating chamber.

In this configuration, the fact that the opening of thesupply/withdrawal passage is positioned in the center of the circularinternal wall surface of the operating chamber allows the operating gasto be efficiently supplied to or withdrawn from the operating chamber.

In another preferred embodiment of the pump for supplying chemicalliquids, the opening of the supply/withdrawal passage is positioned inthe center of the internal wall surface of the operating chamber, withthe internal wall formed symmetrically from its center; and the ventinggroove is formed to be symmetrical, with the center of the opening ofthe supply/withdrawal passage at its center, in correspondence with theinternal wall surface of the operating chamber.

In this configuration, the venting groove is formed to be symmetricalfrom its center positioned at the center of the internal wall surface ofthe operating chamber, where the opening of the supply/withdrawalpassage is positioned. Therefore, if, while a chemical liquid is beingdrawn in, the center of the diaphragm covers the opening of thesupply/withdrawal passage first, this venting groove maintains theinterior of the operating chamber at a stable negative pressure,enabling the diaphragm to stably deform.

In either of the above configurations, the venting groove shouldpreferably have a linear shape.

Such a linear shape allows the venting groove to be easily formed.

The venting groove can also be configured from continuous concave areasobtained by forming a rough internal wall surface in the operatingchamber.

Configuring the venting groove from continuous concave areas obtained byforming a rough internal wall surface in the operating chamber allowsthe venting groove to be easily formed by simply roughening the internalwall surface.

Note that the internal wall surface can be easily roughened by means ofshot blasting, that is, by blasting the surface with abrasive grains.

Preferably, the entire internal wall surface of the operating chambershould be roughened.

According to this configuration, the roughening of the internal wallsurface of the operating chamber is applied to the entire internal wallsurface, which corresponds to the deformation region of the diaphragm.Thus, there is no need to separate the internal wall surface of theoperating chamber into an area that should be roughened and an area thatshould not be roughened, thereby simplifying the operation of rougheningthe internal wall surface. Furthermore, the fact that the entireinternal wall surface of the operating chamber is roughened prevents thediaphragm from blocking the venting groove until the diaphragm deformssufficiently toward the operating chamber, thus ensuring reliableevacuation (drawing out) of the operating gas from the operatingchamber.

In either of the above configurations, the pump housing shouldpreferably be formed to be thin in the deformation direction of thediaphragm.

When the pump housing is formed to be thin in the deformation directionof the diaphragm, the operating chamber must also be formed to be thinin the same direction. Since the resulting structure tends to cause thecenter of the diaphragm to contact the internal wall surface of theoperating chamber first during suctioning of a chemical liquid, thesignificance of providing the venting groove is great.

BRIEF EXPLANATION OF DRAWINGS

[FIG. 1] is a frontal cross-sectional diagram illustrating the pump unitinside the chemical liquid supply system.

[FIG. 2] (a) is a side cross-sectional diagram of the pump unit, and (b)is an enlarged cross-sectional diagram of (a).

[FIG. 3] is a circuit diagram illustrating the entire circuitry of thechemical liquid supply system.

[FIG. 4] (a) is the front view of the pump housing on the operatingchamber side, and (b) is a cross-sectional diagram along line A-A in(a).

[FIG. 5] (a) and (b) are diagrams explaining the operation of thediaphragm.

[FIG. 6] (a) is the front view of the pump housing on the operatingchamber side in another example, and (b) is a cross-sectional diagramalong line B-B in (a).

[FIG. 7] (a) and (b) are diagrams explaining the operation of thediaphragm in another example.

EXPLANATION OF SYMBOLS

22 . . . pump housing; 22 b . . . supply/withdrawal passage; 22 c . . .internal wall surface; 22 d . . . opening; 22 e . . . venting groove; 22f . . . venting groove; 22 g . . . concave area; 23 . . . diaphragm; 25. . . pump chamber; 26 . . . operating chamber; R . . . resist liquid(chemical liquid).

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment in which the present invention is implemented into a pumpunit of a chemical liquid supply system used in a manufacturing line ofa semiconductor device, etc. is explained below, referencing thedrawings. Note that FIG. 1 and FIG. 2 illustrate a pump unit 10, whichis a primary component of the system, while FIG. 3 illustrates theentire chemical liquid supply system.

As shown in FIGS. 1 and 2, the pump unit 10 is formed by assemblingtogether a pump 11, a solenoid switching valve 12, a suction-sideshut-off valve 13, a discharge-side shut-off valve 14, a suckback valve15, a regulator 16, a suction-side passage member 17 and adischarge-side passage member 18.

The pump 11 has a thin flat prism form having a nearly square shape whenviewed from the front, and a pair of pump housings 21 and 22. Concaveareas 21 a and 22 a, opened in almost circular dome shapes, are formedin the center of the opposing faces of pump housings 21 and 22,respectively. In the pump housings 21 and 22, the peripheries of theconcave areas 21 a and 22 a hold and support a diaphragm 23 comprised ofa circular flexible film made of a fluorine resin or the like, and thepump housings 21 and 22 are secured to each other using eight screws 24.

A diaphragm 23 partitions the space formed by the concave areas 21 a and22 a of the pump housings 21 and 22, with the space on the side of pumphousing 21 (the left side of the diaphragm 23 in FIG. 2) used as a pumpchamber 25 and the space on the side of pump housing 22 (the right sideof the diaphragm 23 in FIG. 2) used as an operating chamber 26. The pumpchamber 25 is a space for supplying/withdrawing the resist liquid R (seeFIG. 3) used as a chemical liquid, and the operating chamber 26 is aspace for supplying/withdrawing the operation air for driving thediaphragm 23. Note that in order to reduce the thickness of the pump 11,the pump housings 21 and 22 are made thin (in this case in thedeformation direction of the diaphragm 23), with the result that boththe pump chamber 25 and the operating chamber 26 form thin spaces in thesame direction.

A suction passage 21 b, which is connected to the pump chamber 25 andextends linearly downward, is formed in pump housing 21 on the pumpchamber 25 side. The Suction passage 21 b is connected to suctionpassage 17 a of the suction-side passage member 17. A discharge passage21 c, which is connected to the pump chamber 25 and extends linearlyupward, is also formed in the pump housing 21. Furthermore, thisdischarge passage 21 c is provided on the same line L1 as the suctionpassage 21 b. Since the pump chamber 25 in this embodiment is formed asa thin space in the deformation direction of the diaphragm 23, thesuction passage 21 b and discharge passage 21 c connected to this pumpchamber 25 are bent perpendicularly near the pump chamber 25 to thedegree necessary for connection (roughly equaling the width of thepassage) (see FIG. 2). However, these bends do not significantly impact(create resistance to) the flow of the resist liquid R inside the pump11, but allow the resist liquid R to flow smoothly in these areas.

A supply/withdrawal passage 22 b, which supplies operating air to theoperating chamber 26, is formed in the pump housing 22 on the operatingchamber 26 side. An opening 22 d of the supply/withdrawal passage 22 bon the internal wall surface 22 c of the operating chamber 26 (concavearea 22 a) is positioned in the center of the circular concave area 22a. Furthermore, as shown in FIG. 4, a cross-shaped venting groove 22 e,whose end extends to the periphery of the operating chamber 26, isformed on the internal wall surface 22 c of the operating chamber 26,and the opening 22 d of the supply/withdrawal passage 22 b is positionedin the intersection of the cross-shaped venting groove 22 e. Thissupply/withdrawal passage 22 b is then connected to a solenoid switchingvalve 12 secured to the pump housing 22.

Here, the intake port of the solenoid switching valve 12 is connected toone end of a supply tube 28 as shown in FIG. 3. The supply tube 28 hasan electro-pneumatic regulator 27 in the middle, and the other end ofthe supply tube 28 is connected to a supply source 29 a. Theelectro-pneumatic regulator 27 is adjusted by a controller 50, such thatthe pressure of the operating air supplied from the supply source 29 ato the pump 11 remains constant at a preset value. The exhaust port ofthe solenoid switching valve 12 is connected to a vacuum generationsource 29 b via an exhaust pipe 28 b. The solenoid switching valve 12 iscontrolled and switched by the controller 50 to connect the operatingchamber 26 to either the supply source 29 a or the vacuum generationsource 29 b. This switching action either supplies operating air to orwithdraws it from the operating chamber 26, thereby switching the pump11 between suctioning and discharging actions.

That is, when the action of the solenoid switching valve 12 suppliesoperating air to the operating chamber 26, the interior of the operatingchamber 26 is pressurized, pushing the diaphragm 23 to the pump chamber25 side and discharging the resist liquid R contained inside the pumpchamber 25 to the downstream side via the discharge passage 21 c. Incontrast, when the action of the solenoid switching valve 12 evacuatesthe operating air out of the operating chamber 26 and the pressureinside the operating chamber 26 becomes negative, the diaphragm 23,which has been pushed to the pump chamber 25 side, moves toward theoperating chamber 26, introducing the resist liquid R from the upstreamside into the pump chamber 25 via the suction passage 21 b.

Here, during suctioning of the resist liquid R, the diaphragm 23 deformsto its maximum deformation position to contact the internal wall surface22 c of the operating chamber 26, as shown in FIG. 5 (a). During thisdeformation, the diaphragm 23 tends to deform at its center, as shown inFIG. 5 (b), such that its center may cover the opening 22 d of thesupply/withdrawal passage 22 b before the diaphragm 23 deforms to itsmaximum deformation position. In this case, the opening 22 d isconnected to the venting groove 22 e, which extends to the periphery ofthe operating chamber 26. Consequently, even when the diaphragm 23deforms from the center, thus the center covers the opening 22 d of thesupply/withdrawal passage 22 b first, the venting groove 22 e positionedon the outside of the contacted center is open. Therefore, it ispossible to continue to evacuate the interior of the operating chamber26 through the open venting groove 22 e (the arrow in FIG. 5 (b)indicates the flow of the operating air). As a result, even when suchuneven deformation occurs in the diaphragm 23, the diaphragm 23 stillreliably deforms to its maximum deformation position within a shortperiod, thus shortening the time needed for filling the pump chamber 25with the resist liquid R and ensuring a sufficient charging volume.

A rod-shaped, suction-side passage member 17 is secured to the center ofthe bottom of the pump housings 21 and 22. The suction-side passagemember 17 is disposed along the flat direction of the pump 11. A suctionpassage 17 a, which extends nearly linearly downward, is formed in thesuction-side passage member 17. This suction passage 17 a is disposed onthe same line L1 as the suction passage 21 b of the pump 11. On thesurface of the suction-side passage member 17 where it faces the pumphousing 21, a concave housing section 17 b is formed around the suctionpassage 17 a, and the seal ring 33 is housed inside the concave housingsection 17 b. The seal ring 33 is disposed between the suction-sidepassage member 17 and the pump housing 21, preventing the resist liquidR inside the suction passages 17 a and 21 b from leaking out of the gapbetween the suction-side passage member 17 and the pump housing 21.

The inner peripheral surface 33 a of the seal ring 33 is smoothlycontinuous with the inner peripheral surfaces of the suction passages 17a and 21 b. Specifically, the seal ring 33 has a shape in which theinner peripheral surface 33 a is continuous with the inner peripheralsurfaces of the suction passages 17 a and 21 b, and in which the concavearea gradually deepens toward the outside in the radial direction as thedistance from the internal passages 17 a or 21 b toward the center ofthe seal ring 33 in its thickness direction increases. In other words,this shape allows the resist liquid R to flow smoothly in the seal ring33 area, preventing the resist liquid R and air bubbles from becomingtrapped. Note that using an ordinary seal ring (O-ring) having acircular cross section creates an acute-angled dip between the seal ringand suction passages 17 a and 21 b. This results in a shape that is notsmoothly continuous with the inner peripheral surfaces of the passages17 a and 21 b, and causes the resist liquid R and air bubbles toproblematically become trapped in this area. Additionally, as shown inFIG. 3, the suction-side passage member 17, using a coupling 19 providedat its tip, is connected to one end of a suction tube 31, while theother end of the suction tube 31 is guided into the resist liquid Rcontained inside a resist bottle 30.

The suction-side shut-off valve 13 consisting of an air-operated valveis assembled together with the suction-side passage member 17. Thesuction-side shut-off valve 13 has a nearly square prism shape, and isdisposed in the direction perpendicular to the suction-side passagemember 17 and along the flat direction of the pump 11 (pump housings 21and 22). Here, as shown in FIG. 3, the suction-side shut-off valve 13switches between opening and closing the suction passage 17 a based onthe switching action of an electro-pneumatic regulator 32 that iscontrolled by the controller 50. That is, the suction-side shut-offvalve 13 has the structure shown in FIG. 1. When its supply/withdrawalchamber 13 a is opened to the atmosphere by the switching action of theelectro-pneumatic regulator 32, the valve body 13 b of the suction-sideshut-off valve 13 receives a spring force from a spring 13 c and shutsoff the suction passage 17 a; when operating air is supplied to thesupply/withdrawal chamber 13 a from the supply source 29 a, the valvebody 13 b sinks by working against the spring force of the spring 13 cto open the suction passage 17 a. Note that the part of the suctionpassage 17 a near the valve body 13 b is bent perpendicularly to thedegree necessary for ensuring the reliable opening and closing action ofthe valve body 13 b (roughly equaling the width of the passage).However, this bend does not significantly impact (create resistance to)the flow of the resist liquid R inside the passage member 17, but allowsthe resist liquid R to flow smoothly in this area as well.

The rod-shaped, discharge-side passage member 18 is secured to thecenter of the top of the pump housings 21 and 22. The discharge-sidepassage member 18 is disposed along the flat direction of the pump 11.The discharge passage 18 a, which extends nearly linearly upward, isformed in the discharge-side passage member 18. This discharge passage18 a is disposed on the same line L1 as the discharge passage 21 c ofthe pump 11. On the surface of the discharge-side passage member 18where it faces the pump housing 21, a concave housing section 18 b isformed around the discharge passage 18 a, and a seal ring 34 is housedinside the concave housing section 18 b. The seal ring 34 is disposedbetween the discharge-side passage member 18 and the pump housing 21,preventing the resist liquid R inside the discharge passages 18 a and 21c from leaking out of the gap between the discharge-side passage member18 and the pump housing 21.

Like the aforementioned seal ring 33, the inner peripheral surface 34 aof the seal ring 34 is smoothly continuous with the inner peripheralsurfaces of the discharge passages 18 a and 21 c, resulting in astructure that prevents the resist liquid R and air bubbles frombecoming trapped. Additionally, as shown in FIG. 3, the discharge-sidepassage member 18, using a coupling 20 provided at its tip, is connectedto one end of a discharge tube 35 having a nozzle 35 a on its other end.The nozzle 35 a is orientated downward and disposed in a position thatallows it to drip the resist liquid R onto the center of a semiconductorwafer 37 that is placed on and spins with a spinning platform 36.

A discharge-side shut-off valve 14 consisting of an air-operated valveis assembled together with the discharge-side passage member 18. Thedischarge-side shut-off valve 14 has a nearly square prism shape, and isdisposed in the direction perpendicular to the discharge-side passagemember 18 and along the flat direction of the pump 11 (pump housings 21and 22). Here, as shown in FIG. 3, the discharge-side shut-off valve 14is constructed in the same way as the aforementioned suction-sideshut-off valve 13 and switches between opening and closing the dischargepassage 18 a based on the switching action of an electro-pneumaticregulator 38 that is controlled by the controller 50. That is, thedischarge-side shut-off valve 14 has the structure shown in FIG. 1. Whenits supply/withdrawal chamber 14 a is opened to the atmosphere by theswitching action of the electro-pneumatic regulator 38, a valve body 14b of the discharge-side shut-off valve 14 receives a spring force from aspring 14 c and shuts off the discharge passage 18 a; when operating airis supplied to the supply/withdrawal chamber 14 a from the supply source29 a, the valve body 14 b sinks by working against the spring force ofthe spring 14 c to open the discharge passage 18 a. Note that the partof the discharge passage 18 a near the valve body 14 b is bentperpendicularly to the degree necessary for ensuring the reliableopening and closing action of the valve body 14 b (roughly equaling thewidth of the passage). However, this bend does not significantly impact(create resistance to) the flow of the resist liquid R inside thepassage member 18, but allows the resist liquid R to flow smoothly inthis area as well.

The suckback valve 15 consisting of an air-operated valve is assembledtogether with the discharge-side passage member 18, next to and on thedownstream side of the discharge-side shut-off valve 14. The suckbackvalve 15 also has a nearly square prism shape, and is disposed in thedirection perpendicular to the discharge-side passage member 18 andalong the flat direction of the pump 11 (pump housings 21 and 22). Here,as shown in FIG. 3, the suckback valve 15 is designed to suck back apredetermined amount of the resist liquid R located downstream of thevalve 15 to the upstream side to prevent unintended dripping of theresist liquid R from the nozzle 35 a, based on the switching actions ofan electro-pneumatic regulator 39. That is, the suckback valve 15 hasthe structure shown in FIG. 1. When its supply/withdrawal chamber 15 ais opened to the atmosphere by the switching action of theelectro-pneumatic regulator 39, a valve body 15 b of the suckback valve15 sinks by receiving a spring force from a spring 15 c and enlarges thevolume of the volume-expansion chamber 18 c connected in communicationwith the discharge passage 18 a, sucking in the predetermined amount ofthe resist liquid R into the volume-expansion chamber 18 c. In contrast,when operating air is supplied to the supply/withdrawal chamber 15 afrom the supply source 29, the valve body 15 b protrudes by workingagainst the spring force of the spring 15 c, reducing the volume of thevolume-expansion chamber 18 c provided in the discharge passage 18 a.

Furthermore, the regulator 16 having the shape of an approximaterectangular parallelepiped is secured to the discharge-side passagemember 18 on the side opposite from the discharge-side shut-off valve 14and the suckback valve 15. That is, the regulator 16 is installed on thedischarge-side passage member 18 along the flat direction of the pump11. A base 41 of the regulator 16 is secured to the discharge-sidepassage member 18. A securing platform 42 is secured to the base 41, andthe electro-pneumatic regulators 38 and 39, which switch thedischarge-side shut-off valve 14 and the suckback valve 15, are securedto the securing platform 42. A cover 43 that covers theelectro-pneumatic regulators 38 and 39 is installed on this securingplatform 42. Furthermore, communication passages 45 and 46, which areconnected to the electro-pneumatic regulators 38 and 39, arerespectively formed on the securing platform 42 and the base 41, and arerespectively connected to the supply/withdrawal chambers 14 a of thedischarge-side shut-off valve 14 and the supply/withdrawal chambers 15 aof the suckback valve 15, though not shown in the figure. Based on thecontrol by the controller 50, the electro-pneumatic regulators 38 and 39either supply operating air to or withdraw it from the supply/withdrawalchambers 14 a of the discharge-side shut-off valve 14 and thesupply/withdrawal chambers 15 a of the suckback valve 15, therebyoperating the discharge-side shut-off valve 14 and the suckback valve15.

In the pump unit 10 thus configured, the suction passage 17 a inside thesuction-side passage member 17, the suction passage 21 b and thedischarge passage 21 c inside the pump 11, and the discharge passage 18a of the discharge-side passage member 18, through all of which theresist liquid R passes, are all linear in shape and disposed on the sameline L1. That is, the structure of this pump unit 10 allows the lengthof the resist liquid R passage to be short as much as possible, whilenearly eliminating areas inside the resist liquid R passage where theresist liquid R or air bubbles could become trapped. The structure ofthe seal rings 33 and 34 also nearly eliminates areas where the resistliquid R or air bubbles could become trapped.

As shown in FIG. 3, the controller 50 controls a series of actions ofthe chemical liquid supply system, by controlling the electro-pneumaticregulator 27 to set the operating air supplied to the pump 11 at thepredetermined pressure level, and also by controlling the solenoidswitching valve 12, which switches and operates the pump 11; theelectro-pneumatic regulator 32, which switches and operates thesuction-side shut-off valve 13; and the electro-pneumatic regulators 38and 39, which operate the discharge-side shut-off valve 14 and thesuckback valve 15.

That is, when a command to begin the operation of the chemical liquidsupply system is generated, the controller 50 first controls theelectro-pneumatic regulator 32 to switch the suction-side shut-off valve13, shutting off the suction passage 17 a. This action cuts the pump 11off from the resist bottle 30. The controller 50 also switches thesolenoid switching valve 12 to supply operating air adjusted to thepredetermined pressure to the operating chamber 26 inside the pump 11.This action causes the diaphragm 23 to, move toward the pump chamber 25,pressurizing the resist liquid R contained inside the pump chamber 25.During this process, the discharge passage 18 a is shut off by thedischarge-side shut-off valve 14 on the downstream side of the pump 11,preventing discharge of the resist liquid R.

Next, the controller 50 controls the electro-pneumatic regulator 38 toswitch the discharge-side shut-off valve 14, opening the dischargepassage 18 a, and also controls the electro-pneumatic regulator 39 tocancel the sucking-in of the resist liquid R by the suckback valve 15.During this process, the resist liquid R inside the pump chamber 25,pressurized by the diaphragm 23, is discharged from the pump 11, and apredetermined amount of this resist liquid R is dripped onto asemiconductor wafer from the nozzle 35 a at the tip of the dischargepipe 35 via the discharge passage 18 a.

Next, the controller 50 controls the electro-pneumatic regulator 38 toswitch the discharge-side shut-off valve 14, shutting off the dischargepassage 18 a. This action stops the discharge of the resist liquid Rfrom the nozzle 35 a. The controller 50 also controls theelectro-pneumatic regulator 39 to cause the suckback valve 15 to draw ina predetermined amount of the resist liquid R, preventing unintendeddripping of the resist liquid R from the nozzle 35 a.

Next, the controller 50 controls the electro-pneumatic regulator 32 toswitch the suction-side shut-off valve 13, opening the suction passage17 a. This action connects the pump 11 to the resist bottle 30. Thecontroller 50 also switches the solenoid switching valve 12, causing theoperating air to be suctioned from the operating chamber 26 by means ofthe vacuum generation source 29 b. Then, the pressure inside theoperating chamber 26 becomes negative, with the result that thediaphragm 23 deforms to its maximum deformation position to contact theinternal wall surface 22 c of the operating chamber 26 and the resistliquid R is suctioned into and fills the pump chamber 25.

During this suctioning, if the center of the diaphragm 23 first coversthe opening 22 d of the supply/withdrawal passage 22 b, the opening 22 dis connected to the venting groove 22 e, which extends to the peripheryof the operating chamber 26, causing the evacuation of the interior ofthe operating chamber 26 to continue through the venting groove 22 epositioned on the outside of the center that is contacted first.Therefore, even when such uneven deformation occurs in the diaphragm 23,the diaphragm 23 can reliably deform to its maximum deformation positionwithin a short period, thus shortening the time needed for filling thepump chamber 25 with the resist liquid R and ensuring a sufficientcharging volume. From this point on, the controller 50 repeats theaforementioned actions such that a predetermined amount of resist liquidR is dripped onto each semiconductor wafer 37, as they are carried inone after another.

Next, the characteristic effects of such an embodiment are described.

In the present embodiment, the opening 22 d of the supply/withdrawalpassage 22 b is positioned in the center of the internal wall surface 22c of the operating chamber 26 (concave area 22 a), and the cross-shapedventing groove 22 e, which extends from the opening 22 d of thesupply/withdrawal passage 22 b toward the periphery of the internal wallsurface 22 c, is formed on the internal wall surface 22 c. Duringsuctioning of the resist liquid R, the operating air the operatingchamber 26 is evacuated through the supply/withdrawal passage 22 b. Inthis case, the diaphragm 23 tends to deform in its center, which maycover the opening 22 d of the supply/withdrawal passage 22 b first.However, in the present embodiment, the opening 22 d of thesupply/withdrawal passage 22 b is connected to the venting groove 22 e,which opens toward the periphery of the operating chamber 26. Therefore,even when the diaphragm 23 deforms in this manner, the venting groove 22e positioned on the outside of the contacted center is open, making itpossible to continue to evacuate the operating air inside the operatingchamber 26 through the open venting groove. As a result, even when suchuneven deformation occurs in the diaphragm 23, the diaphragm 23 canreliably deform to its maximum deformation position toward the operatingchamber 26 within a short period, thus shortening the time needed forfilling the pump chamber 25 with the resist liquid R and ensuring asufficient charging volume.

In the present embodiment, the fact that the opening 22 d of thesupply/withdrawal passage 22 b is positioned in the center of thecircular internal wall surface 22 c of the operating chamber 26 allowsthe operating air to be efficiently supplied to or withdrawn from theoperating chamber 26.

In the present embodiment, since the venting groove 22 e extends to theperiphery of the operating chamber 26, the diaphragm 23 can be preventedfrom blocking the venting groove 22 e until the diaphragm 23 deformssufficiently toward the operating chamber 26, thus ensuring reliableevacuation of the operating air inside the operating chamber 26.

In the present embodiment, the venting groove 22 e is formed in asymmetric cross shape, with its center positioned at the center of theinternal wall surface 22 c of the circular operating chamber 26 (concavearea 22 a), which has a symmetric shape. Therefore, during suctioning ofthe resist liquid R, even if the center of the diaphragm 23 covers theopening 22 d of the supply/withdrawal passage 22 b first, the ventinggroove 22 e maintains the pressure inside the operating chamber 26 at astable negative pressure, enabling the diaphragm 23 to stably deform.

In the present embodiment, the venting groove 22 e is designed to have alinear shape, which allows it to be easily formed.

In the present embodiment, since the pump housing 22 is formed to bethin in the deformation direction of the diaphragm 23 in order to makethe pump 11 thin, the operating chamber 26 is also formed to be thin inthe same direction. Because the resulting structure tends to cause thecenter of the diaphragm 23 to contact the internal wall surface 22 c ofthe operating chamber 26 first during suctioning of the resist liquid R,the significance of providing the venting groove 22 e is great.

Note that the present invention is not limited to the described contentsof the aforementioned embodiment and may be implemented in other ways,as in the following examples.

In the aforementioned embodiment, the cross-shaped venting groove 22 eis formed on the internal wall surface 22 c of the operating chamber 26(concave area 22 a). However, the shape of the venting groove is notlimited to such a shape. Although the venting groove 22 e has a crossshape that extends in all four directions from the opening 22 d, it canalso have a Y shape that extends in three directions, for example. Theventing groove may also have a shape that extends in any other odd oreven number of directions. Note that when changing the shape of theventing groove, it is desirable to position the venting groove as closeas possible to the periphery of the operating chamber, and it is best toextend the venting groove to the periphery of the operating chamber 26(concave area 22 a) as in the aforementioned embodiment.

Furthermore, as indicated by the dots in FIG. 6, it is also possible toform the entire internal wall surface 22 c of the operating chamber 26as a rough surface, and configure a venting groove 22 f with continuousindividual concave areas 22 g obtained by roughening the surface, asindicated by the dash line in FIG. 7 (b). With such a configuration,even when the center of the diaphragm 23 covers the opening 22 d of thesupply/withdrawal passage 22 b first during suctioning of the resistliquid R as shown in FIG. 7 (a), the opening 22 d is connected to theventing groove 22 f, which extends to the periphery of the operatingchamber 26 as the continuation of the concave areas 22 g. This allowsthe evacuation of the interior of the operating chamber 26 to continuethrough the venting groove 22 f, which is positioned on the outside ofthe contacted center. (In FIG. 7 (b), the arrow indicates the flow ofthe operating air.) Such a configuration also provides similar effectsto those provided by the embodiment described above.

Note that the internal wall surface 22 c can be easily roughened bymeans of shot blasting, that is, by blasting the surface with abrasivegrains. Moreover, since the entire internal wall surface 22 c isroughened, there is no need to mask an area of the internal wall surface22 c that should not be roughened, thus simplifying the operation ofroughening the internal wall surface 22 c.

In the aforementioned embodiment, the opening 22 d of thesupply/withdrawal passage 22 b is positioned at the center of theoperating chamber 26 (concave area 22 a), but it can also be offset fromthe center.

In the aforementioned embodiment, the pressure inside the operatingchamber 26 is set to be negative during suctioning of the resist liquidR. However, the operating chamber 26 can also be opened to thesurrounding atmosphere. In this case, the interior of the resist bottle30, for example, must be pressurized.

In the aforementioned embodiment, the pump unit 10 is comprised of thepump 11, which acts as a pump for supplying chemical liquids and intowhich shut-off valves 13 and 14, the suckback valve 15, or the like areintegrated. However, other configurations that have at least the pump 11body can also be used.

In the aforementioned embodiment, an explanation is provided usingoperating air as an example. However, it is also possible to use anothergas such as nitrogen in place of air.

In the aforementioned embodiment, an example using the resist liquid Ris described. This is because the target onto which the chemical liquidis to be dripped is assumed to be a semiconductor wafer 37. However,other chemical liquids and other chemical liquid dripping targets mayalso be used.

1. In a pump for supplying chemical liquids in which a pump chamber andan operating chamber are divided by means of a diaphragm comprised of aflexible film, the diaphragm deforms toward the pump chamber when theinterior of the pump chamber is pressurized using an operating gas,thereby discharging the chemical liquid that has been supplied into thepump chamber; and when the interior of the operating chamber reaches anegative pressure because of the withdrawal of the operating gas or whenthe interior of the operating chamber is opened to the surroundingatmosphere, the diaphragm deforms toward the operating chamber, therebydrawing a chemical liquid into the pump chamber, and a supply/withdrawalpassage for supplying the operating gas to or withdrawing same from theoperating chamber is formed in the pump housing, and an opening of thesupply/withdrawal passage is provided in part of the internal wallsurface of the operating chamber, and a venting groove that extends fromthe opening of the supply/withdrawal passage to the periphery of theinternal wall surface is formed on the internal wall surface of theoperating chamber.
 2. The pump for supplying chemical liquids accordingto claim 1, wherein the internal wall surface of the operating chamberis circular in shape, and the opening of the supply/withdrawal passageis positioned in the center of the internal wall surface of theoperating chamber.
 3. The pump for supplying chemical liquids accordingto claim 1, wherein the opening of the supply/withdrawal passage ispositioned in the center of the internal wall surface of the operatingchamber with the internal wall formed symmetrically from its center; andthe venting groove is formed to be symmetrical, with the center of theopening of the supply/withdrawal passage at its center, incorrespondence with the internal wall surface of the operating chamber.4. The pump for supplying chemical liquids according to claim 1, whereinthe venting groove is linear in shape.
 5. The pump for supplyingchemical liquids according to claim 1, wherein the venting groove isconfigured from continuous concave areas obtained by forming a roughinternal wall surface in the operating chamber.
 6. The pump forsupplying chemical liquids according to any of claim 5, whereinroughening of the internal wall surface of the operating chamber isapplied to the entire internal wall surface.
 7. The pump for supplyingchemical liquids according to claim 1, wherein the pump housing isformed to be thin in the deformation direction of the diaphragm.
 8. Thepump for supplying chemical liquids according to claim 2, wherein theventing groove is linear in shape.
 9. The pump for supplying chemicalliquids according to claim 2, wherein the venting groove is configuredfrom continuous concave areas obtained by forming a rough internal wallsurface in the operating chamber.
 10. The pump for supplying chemicalliquids according to claim 9, wherein roughening of the internal wallsurface of the operating chamber is applied to the entire internal wallsurface.